Metachromatic dye-Ca++ATPase method in pathological muscle: a study of 382 muscle biopsies

The metachromatic dye-Ca++ATPase method, that in normal muscle distinguishes fiber types on the basis of their metachromatic or orthochromatic staining, was applied to 382 pathological muscle biopsies. Results were compared in serial sections with those obtained with the conventional ammonium sulphide method. In pathological muscle the metachromatic dye-Ca++ATPase method confirms the advantages already showed in normal muscle: fast and easy performance, neat fiber typing, simultaneous staining of nuclei. Moreover in pathological muscle the metachromatic dye-Ca++ATPase method showed some muscle changes which are missed by the conventional ammonium sulphide one, namely central nuclei, macrophagic invasion and some structural abnormalities. This allows immediate correlation between those alterations and fiber typing.